Portable lighting product, a portable lighting product circuit and a functioning method for a portable lighting product circuit

ABSTRACT

The present invention relates to a circuit for a portable lighting product such as flashlight, lantern, desk lamp, area light, combination area light and flashlight, front and rear bicycle light, emergency light, night light, rechargeable versions of any of those products previously mentioned, in which several power sources are provided. The invention includes the feature that each power source is electrically isolate from each other by the switch in mechanism or mechanisms, when the portable lighting product is switched to the off condition. The power sources can include single dry cells, or sets of series connected dry cells of any number.

FIELD OF THE INVENTION

The present invention relates to a portable lighting product, a portablelighting product circuit and a method of operating a portable lightingproduct circuit, and more particularly to portable lighting productsincluding flashlights and bicycle lights, camping lights and otherportable lighting products.

BACKGROUND OF THE INVENTION

In many applications of portable lighting products, users are ultimatelyconcerned with such factors as bulk of product and the running life ofthat product. For example for flashlights with 6 or 8 dry cells inseries, these may need to be replenished or replaced either at the startof a shift or during a shift and the human condition will dictate thatit will be at the worst possible time.

Generally with 6 and 8 dry cell flashlights, the dry cells are connectedin series in a straight line making the bodies of the flashlightsrelatively long. This can render such flashlights as menacing to thegeneral public because of a club like appearance. Also their relativelylong length renders them difficult to store in cupboards and vehicles,or when carried on belts they can interfere with the wearer's movement.Such flashlights can at times be any thing up to 1 meter or 39 incheslong.

Also, in today's market, brighter operating lamps are being developed,but at the relatively high voltages of 9 or 12 volts, the filaments ofsuch lamps are relatively fragile. Such fragility can b directlyproportional to the voltage at which the lamp is operated.

Whilst a solution to the first and second mentioned difficulties can beto provide the power supply from sets of dry cells in parallel, thissolution results in an additional problem. When sets of series connecteddry cells are connected in parallel, there are risks of dissipation andtransfer of energy from one set of dry cells to another, when they arenot powering a lamp. This can lead to premature dissipation of theavailable energy in the dry cells. Potential risks of prematuredissipation is one reason why manufacturers have not utilised paralleldry cell arrangements for dry cell powered products.

It is an object of the invention to provide a portable lighting product,a portable lighting product circuit and a method of functioning of aportable lighting product circuit which ameliorates, at least partially,at least one of the disadvantages of the prior art.

Whilst the following discussion and description of the embodimentsrelates in part to flashlights, it will be understood that the inventionis applicable to any portable lighting product, and can be readilyincorporated therein without departing from the scope of the followinginventions.

SUMMARY OF THE INVENTION

The present invention provides an electrical circuit for a portablelighting product which includes a lamp holder means and one power sourceholding means to hold at least two power sources, said power sourceholding means having one set of positive and negative terminals for eachpower source that it is to hold, said sets of terminals being adapted tobe electrically connected in parallel with at least one other set ofpositive and negative terminals that function as electrical connectionsfor said lamp holder within said electrical circuit, said circuit beingsuch that when said circuit is closed said positive terminals of saidsets are connected in parallel with said positive terminal of said lampholder and said negative terminals of said sets are connected inparallel with the negative terminal of said lamp holder and when saidcircuit is open at least one terminal, for each power source, of saidpower source holding means is electrically isolated.

The present invention provides an electrical circuit for a portablelighting product which includes a lamp holder means and at least twopower source holding means each to hold at least one power source, eachof said power source holding means having one set of positive andnegative terminals for each power source that it is to hold, said setsof terminals being adapted to be electrically connected in parallel withat least one other set of positive and negative terminals that functionas electrical connections for said lamp holder within said electricalcircuit, said circuit being such that when said circuit is closed saidpositive terminals of said are connected in parallel with said positiveterminal of said lamp holder and said negative terminals of said setsare connected in parallel with the negative terminal of said lamp holderand when said circuit is open at least one terminal, for each powersource, of said power soul holding means is electrically isolated.

Preferably said power source holding means will hold only one powersource.

Preferably, wherein connection in parallel when the circuit is closedand the electrical isolation when the circuit is open, are eachperformed by a single action.

Preferably the single action closes or opens individual switchesassociated with said power sources.

Preferably the isolation of said sets of series connected dry cellsoccurs at one of the following: on the positive side of said powersources; on the negative side of said power sources; on both thenegative side and positive sides of said power sources; or on acombination of the positive and negative sides of said power sources.

Preferably said two switches and said single action is achieved by meansof a double pole double throw switch.

Preferably each power source is located in a separate container orhousing for each set.

Preferably all of said power sources are located in a single containerhaving appropriate electrical connections with said circuit.

Preferably said lamp holder means has a lamp means which is selectedfrom one of the following: a halogen type; a krypton type; a vacuumtype; a xenon type; a lamp means which includes a filament encased in anatmosphere of a gas or combination of gases.

Preferably said power source is a single dry cell.

Preferably said power source is effectively a single dry cell made up ofa set of series connected dry cells.

Preferably said power source is a set of series connected dry cells.

Preferably said dry cells are selected from one of the following sizesor types: AA size, AAA size, C size, D size, lantern type, 9 voltrectangular type. Preferably said portable lighting product is selectedfrom any one of the following products: flashlight, lantern, desk lamp,area light, combination area light and flashlight, front and rearbicycle light, emergency light, night light, rechargeable versions ofany of those products previously mentioned.

The invention also provides a portable lighting product which includes alamp holder means having two terminals with a first terminal beingadapted to be in electrical connection with a first terminal of each ofat least two power sources; a second terminal of said lamp holder beingadapted to be electrically connected to a second terminal of each ofsaid at least two power sources, said circuit including at least oneswitching mechanism which electrically isolates each power source fromeach other when said at least one switching mechanism is in a firstcondition, but when in a second condition said circuit is closed by saidfirst terminals of said sets being connected in parallel with said firstterminal of said lamp holder and said second terminals of said setsbeing connected in parallel with the second terminal of said lampholder.

The invention also provides a portable lighting product which includes alamp holder means with two terminals having a first terminal adapted tobe electrically connected to a first terminal of each of at least twopower sources, the second terminal of each of said at least two powersources being adapted to be electrically connected to a switchmechanism, whereby the second terminal of said lamp holder means isadapted to be selectively electrically connected to said second terminalof said power sources when said switch mechanism is in a first conditionsuch that each of said power sources are electrically connected to saidlamp holder means in parallel, said switch mechanism being adapted toadopt a second condition at which each of said power sources areelectrically isolated from each other.

Preferably said portable lighting product also includes at least onehousing for each of said power sources.

Preferably said portable lighting product includes at least one housingwhich can hold more than one power source.

Preferably in the electrical connection of said second terminal of saidpower sources to said switch mechanism or from said first terminal ofsaid lamp holder means to said first end of said power sources anotherswitch is located in each connection or in at least one group ofconnections.

Preferably when there is said another switch in each connection, saidanother switch is of the single pole single throw variety.

Preferably when there is said another switch in at least one group ofconnections, said another switch has as at least the same number ofpoles as the numbers of said connections it is connected into.

If there are two or more power sources, preferably said switch mechanismconnects said two, or any two, if there are more than two power sources,into electrical connectivity in parallel with said lamp holder means.

Preferably said switching mechanism has or another switching mechanismhas means for an operator to select at any time, which power source orgroups of power sources are to be connected in parallel with each otherand said lamp holder means, if more than two power sources are present.

Preferably said lamp holder means can receive a lamp means which is onof the following types: a halogen type; a krypton type; a vacuum type; axenon type; a lamp means which includes a filament encased in anatmosphere of a gas or combination of gases.

Preferably said power source is a single dry cell.

Preferably said power source is effectively a single dry cell made up ofa set of series connected dry cells.

Preferably said power source is a set of series connected dry cells.

Preferably said dry cells are selected from one of the following sizesor types: AA size, AAA size, C size, D size, lantern type, 9 voltrectangular type.

Preferably said portable lighting product is selected from any one ofthe following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, rechargeable versions of any of thoseproducts previously mentioned.

A further invention provides a portable lighting product which includesa lamp holder means having two terminals with a first terminal beingadapted to be in electrical connection with a first terminal of at leasttwo power sources and a second terminal of said lamp holder means beingadapted to be electrically connected to a second terminal of said atleast two power sources, said circuit including at least one switchingmechanism which electrically isolates each of said power sources butallowing only one of said power sources to be in electrical connectionwith said lamp holder means at any time.

Preferably said portable lighting product is selected from any one ofthe following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, rechargeable versions of any of thoseproducts previously mentioned.

The invention also provides a functioning method for a portable lightingproduct circuit for disconnecting from said portable lighting productcircuit more than one power sources which are or could be connected inparallel with a lamp holder means in said portable lighting productcircuit, said method including the step of electrically isolating eachof said power sources from each other power source when they are notelectrically connected to said lamp holder means.

Preferably said power source is a single dry cell.

Preferably said power source is effectively a single dry cell made up ofa set of series connected dry cells.

Preferably said power source is a set of series connected dry cells.

Preferably said dry cells are selected from one of the following sizesor types: AA size, AAA size, C size, D size, lantern type, 9 voltrectangular type.

Preferably said portable lighting product is selected from any one ofthe following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, rechargeable versions of any of thoseproducts previously mentioned.

The invention also provides a portable lighting product including ahousing defining respective chambers for a plurality of power sources; alight source portion associated with said housing including a holder fora lamp; and electrical circuit means including switching meansadjustable between a first condition in which the lamp holder iselectrically connected in parallel with said power sources, and a secondcondition in which the switch breaks respective electrical circuitslinking said lamp holder and the power sources and linking the sets ofpower sources.

Preferably said power source is a single dry cell.

Preferably said power source is effectively a single dry cell made up ofa set of series connected dry cells.

Preferably said power source is a set of series connected dry cells.Preferably said dry cells are selected from one of the following sizesor types: AA size, AAA size, C size, D size, lantern type, 9 voltrectangular type.

Preferably said portable lighting product is selected from any one ofthe following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, rechargeable versions of any of thoseproducts previously mentioned.

The embodiments of the present invention provide the advantage ofensuring that each power source or set of series connected dry cells aredisconnected from the circuit with the lamp holder means, as well aseach of the other power sources or sets of series connected dry cells.By being so, the embodiment of the invention ensures that the powersources or sets of dry cells are prevented from dissipating prematurely.

When this advance is coupled with the advances in lamps and theirability to luminesce to a greater degree at lower voltages, and the factthat such lamps are more susceptible to damage when operated at highervoltages, a longer life of lamp may result together with a relativelyunnoticeable reduction in the luminescence of the lamp.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be describe by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is a schematic diagram of a flashlight circuit which is anembodiment of the present invention;

FIG. 2 is an end view of a switching mechanism for use with theembodiment of FIG. 1;

FIG. 3 is a side view of the apparatus of FIG. 2;

FIG. 4 is a printed circuit board for use with the apparatus of FIG. 1;

FIGS. 5, 6, 7, 8, 9 and 10 illustrate a perspective, back, top, side,bottom and front views of a flashlight which can utilise the presentinvention;

FIGS. 11 through to 16 illustrate a perspective, back, top, side, bottomand front views of a flashlight similar to that of FIGS. 5 to 10, havingthree power source housings;

FIGS. 17 through to 22 illustrate a perspective, back, top, side, bottomand front view. of a flashlight, similar to that of FIGS. 5 to 10,having four power source housings;

FIG. 23 illustrates a schematic of a portable lighting product circuitfor use with the flashlight of FIGS. 11 to 16;

FIG. 24 illustrates a schematic of a portable lighting product circuitfor use with the flashlight of FIGS. 17 to 22;

FIG. 25 illustrates a schematic of a circuit similar to that of FIG. 1wherein only two single power sources are present;

FIG. 26 illustrates a schematic of a circuit similar to that of FIG. 23wherein three single power sources are present; and

FIG. 27 illustrates a schematic of a circuit similar to that of FIG. 24wherein four single power sources are present.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Illustrated in FIG. 1 is a portable lighting product circuit 2. In theportable lighting product circuit 2 is a lamp 4A in a lamp holder 4which includes a ground terminal or body 6 which makes contact with aground terminal of a lamp 4A. The lamp 4A held by the lamp holder 4 canbe of any sort but is preferably of the halogen or krypton type whichoperate at 3.6 volts or 4.7 volts. The ground terminal 6 is electricallyconnected by an electrical connection means 7 (which can be a wire orother electrical connection means such as a printed circuit board track,a case connection or a combination of such electrical connection means.These will be hereinafter referred to as “electrical connection means”)to the negative ends 16 and 18 of two power sources 20 and 22 each madeup of a set of three series connected dry cells 24. Each of the threeseries connected dry cells 24 in each power source 20 and 22 are all thesame size, generally of the AA, AAA, C, D size and are approximately of1 to 1.5 volts of electrical potential. Alternatively the dry cellscould each be of the lantern type or rectangular 9 volt type These areconnected positive end to negative end in a series connection as iscommonly known in the art, in each of the power sources 20 and 22.

A second terminal 8 of lamp holder 4 is electrically connected by anelectrical connection means 10 to two parallel connected poles, thefirst being pole 12 and the second being pole 14, An electricalconnection means 26 connects the positive end 28 of the first powersource 20 to pole 34 whilst an electrical connection means 30 connectsthe positive end 32 of the power source 22 to pole 36.

The circuit between the pole 34 and pole 14 can be closed by means ofswitching mechanism 38. Whereas the circuit between the pole 36 and thepole 12 can be closed by the switching mechanism 40. The switchingmechanisms 38 and 40 are combined into a single switch 42 which is adouble pole, double throw switch. Preferably the switch 42 is of smallproportions, such as one having a length and width of approximatley 10mm. The double pole, double throw switch is utilised so that a singleaction of the operator moving the switch to a first condition willelectrically isolate each power source 20 and 22 when the lamp 4A in thelamp holder 4 is not emitting light (ie the portable lighting product inwhich the circuit is installed is switched off). The double pole doublethrow switch 42 when moved to a second condition puts both power sources20 and 22 in parallel connection with the lamp holder 4.

In an alternative embodiment, the portable lighting product circuit 2can be modified by the switch 42 being substituted by a switchingmechanism that operates each switching mechanism 38 and 40 individuallyor alternately by the operators action. In particular the switches 38and 40 could be individual switches and individually opened or closed.In this case the operator will know that either or both or none of thepower sources 20 or 22 are connected in the circuit because the lamp 4Ain the lamp holder 4 will be emitting light, albeit at low wattage ifonly one is connected.

In a still further embodiment, the portable lighting product circuit 2of FIG. 1 can be modified by the addition of a single pole, single throwswitch in the electrical connection means 26 and 30. These additionalswitches can be the same as switches 64 and 66 of FIGS. 23 and 24. Inthis embodiment an operator can select either one or both of the powersources 20 or 22 by closing one or both of the single pole single throwswitches respectively. This will identify or set which power source (20or 22 or both) will supply current to the lamp holder 4 when the switchmechanisms 40 and 38 are closed in the switch 42.

The principles and modifications and features discussed in the previoustwo paragraphs can also be applied to the circuits of FIGS. 23 to 27inclusive.

As illustrated in FIGS. 2, 3 or 4 the switching mechanism 42 has sixterminals and is used as a double pole double throw switch. However, forthe embodiment illustrated in FIGS. 1 and FIGS. 5 to 10, the poles 1 and3 as illustrated in FIG. 4 are not connected into the circuit. The poles12 and 14 are common and connected to a common terminal 8 by electricalconnection means 10 whereas poles 36 and 34 are the terminations ofelectrical connection means 26 and 30.

In the end view of FIG. 2 the switch 42 is in the off condition, whereasthe switch 42 in the side view of FIG. 3 is switched to the oncondition, which is done by the depression of the button 41 in thedownward direction of arrows 43.

When the switch 42 is in a condition at which the portable lightingproduct circuit 2 is switched “off”, the poles 1 & 12 and 3 & 14 areclosed (or electrically connected) whereas poles 12 & 36 and 14 & 34 areopen (or not electrically connected). Whereas when the portable lightingproduct circuit 2 is in the “on” condition, poles 1 & 12 and 3 & 14 areopen (or not electrically connected) and poles 12 & 36 and 14 & 34 areclosed (or electrically connected).

The portable lighting product circuit 2 illustrated in FIG. 1 can beinstalled in the flashlight 49 of FIGS. 5 to 10.

In the flashlight 49 illustrated in FIGS. 5 to 10, each power source 20and 22 is physically isolated from each other inside power sourcehousings 50 and 52 respectively. Each power source housing 50 and 52 isclosed by a sealed and screwed on end cap 51. The portable lightingproduct circuit 2 of FIG. 1 can be installed in any appropriate locationinside the body of flashlight 49. As can be seen from FIGS. 7 and 8, theswitch 42 is located in the vicinity of the terminus of the power sourcehousings 50 and 52. Some other components of the portable lightingproduct circuit 2 can be located in the region between the termini ofthe power source housings 50 and 52 and the lamp end 41.

Illustrated in FIGS. 11 to 16 is an embodiment similar to that of FIGS.5 to 10, wherein three power source housings 50, 52 and 160 areprovided. With this embodiment, the portable lighting product circuit 2Aof FIG. 23 can be utilised.

In FIGS. 11 to 16 like features with FIGS. 5 to 10 have been likenumbered and the same is the case with FIGS. 1 and 23.

The power source housing 160 (see FIG. 11) houses power source 60 (seeFIG. 23) including three series connected dry cells 24 (see FIG. 23). InFIG. 23 there is positioned in the circuit 2A a three pole switch 62which activates switch mechanisms 38, 40 as in FIG. 1, but as well, anadditional switch mechanism 73 which when closed electrically connectspoles 72 and 74.

In the electrical connection means 26, 30 and 68, from the positive endsof the power sources 20, 22 and 60 and the respective poles 34, 36 and72, are located single pole single throw switches 64, 66 and 70. Theseswitches allow an operator to select either one of power sources 20, 22and 60, or groups of them such as any two or all three of them, to beconnected in parallel with the lamp holder 4, when the three pole switch62 is activated, by closing switch mechanisms 73, 40 and 38 which willclose the circuits between poles 74 & 72, 12 & 36 and 14 & 34. 17 to 22illustrate a four power source housing flashlight similar to FIGS. 11 to16 and like parts have been like numbered. FIG. 24 is an illustration ofa circuit 2B embodying the invention for use with the flashlight ofFIGS. 17 to 22. Like parts of FIG. 24 have been like numbered with likeparts of FIG. 23.

In FIGS. 17 to 22 a fourth power source housing 180 is incorporated inthe flashlight of these figures. The additional or fourth power sourcehousing 180 houses power source 80 (of FIG. 24) and includes a set ofthree series connected dry cells 24 as illustrated in FIG. 24. Thecircuit 2B in FIG. 24 differs from the circuit 2A of FIG. 23 by theaddition of: the power source 80 of three series connected dry cells;electrical connection means 82 from the positive end of the power source80 to pole 86; parallel pole 90 on the lamp holder 4 side of the circuit2B; switch mechanism 84 which serves the same function as switchmechanisms 64, 66 and 70 for the power source 80; and the substitutionof the 3 pole switch 62 by a 4 pole switch 88, and a parallel connectionto the other negative ends of the power sources 20, 22 and 60.

The circuit 2B of FIG. 24 functions in a similar manner to that of FIG.23, in that the operator can select any one power source, group of twopower sources, group of three power sources or all four power sources20, 22, 60 and 80. However with an even number power sources 20, 22 60and 80, double pole double throw switches similar to 42 can be connectedinto electrical connection means 26 & 30, and 68 & 82, so as to selecttwo power sources such as 20 & 22 or 60 & 80 at a time.

If desired a single power source housing can be utilised to house allthe power sources in such a way that the individual cells of each setare connected in series and in accordance with circuits of FIGS. 1, 23or 24.

If the number of power sources is required to exceed that illustrated inFIGS. 1, 23 or 24, then the switching mechanisms will need to becommensurately altered and further electrical connection means added andif required single pole single throw switches for the selection of thepower source or power sources. The proviso being that when the portablelighting product is switched off, the switch mechanisms electricallyisolate all power sources with respect to each other.

Whilst in the above descriptions of the embodiments the switches andswitching mechanisms are located on the positive side of the powersource in the circuit, the switches and switching mechanisms could belocated on the negative side as well. If there is more than one type ofswitch as in FIGS. 23 and 24, they may be on either the positive andnegative sides of the circuit or on both sides of the circuit, or on thepositive side of a first power source, the negative side of an adjacentpower source and so on.

Preferably, the dry cells 24 are first installed in series connectioninto a cartridge mechanism to hold the sets of serially connected drycells together to thereby form the power sources 20, 22 60 or 80, whereupon they can then be placed inside the power source housings 50, 52 160or 180 and the housings sealed by end caps 51 making the necessaryconnections into the open circuit or closed circuit if the appropriateswitches are closed.

It may be desired to also associate with each set of series connecteddry cells or power source, by providing appropriate circuitry, a batterylife indicator so that an operator will be aware of the status of eachpower source 20, 22, 60 or 80.

The life of a dry cell is impacted by the rate at which current is drawnfrom the dry cell. When all of the dry cells in a portable lightingproduct are connected in series they are exposed to the same drain ratewhen a portable lighting product is switched on. However, if the exactsame dry cells are connected in two equal numbered groups of seriesconnected sets which are then connected in parallel, the drain rate percell may be reduced somewhere in the range of 35% to 60% by comparisonto the same number of cells all connected together by seriesconnections. This reduction in drain rate allows the dry cells todischarge more efficiently and can thus improve the life or run time ofthe portable lighting product or other apparatus.

Illustrated in FIGS. 25, 26 and 27 are circuits 2C, 2D and 2Erespectively. In these circuits the power sources 20, 22, 60 and 80, areeach illustrated as being comprised of only one dry cell 24.Alternatively, the power sources 20, 22, 60 and 80 could be comprised oftwo or more series connected dry cells. It is envisaged that sets ofseries connected dry cells can be pre packaged, and would be sold forinstallation in equipment which incorporates any of the above describedcircuits. Alternatively, cartridges holding a predetermined number ofappropriately sized dry cells could receive individual cells and whichcan then be installed in the portable lighting product. The circuits 2C,2D, and 2E of FIGS. 25, 26 and 27 respectively, operate in the samemanner as those of FIGS. 1, 23 and 24.

Whilst the above description refers to flashlights and portable lightingproducts generally, it will be understood that the inventions describedare applicable to any dry cell powered portable lighting devices suchas: torches, flashlights, lanterns, desk lamps, area lights, combinationarea flashlights, front bicycle lights, rear bicycle lights, emergencylights, night lights, and rechargeable versions of any of those productspreviously mentioned.

Whilst the above portable lighting products may be supplied with drycells and power sources in the housings and chambers, they could betypically sold without said power sources and dry cells.

The foregoing describes embodiments of the present invention andmodifications by those skilled in the art can be made thereto withoutdeparting from the scope of this invention.

What is claimed is:
 1. An electrical circuit for a portable lightingproduct comprising: a lamp holder having a positive terminal and anegative terminal; a power source holder for holding at least two powersources, said power source holder having one set of positive andnegative terminals for each power source that it is to hold, said setsof terminals being adapted to electrically connect the power sources inparallel with one another; and a switch mechanism coupled in seriesbetween said parallel power sources and said lamp holder such that, whensaid switch is open, said power sources are electrically isolated fromone another, and when said switch is closed, at least one of said powersources may be electrically connected to said lamp holder.
 2. Thecircuit as defined in claim 1, wherein said switch mechanism isconfigured to connect said power sources in parallel when said switchmechanism is closed and to electrically isolate said power sources whenthe circuit is opened by a single actuation of said switch mechanism. 3.The circuit as defined in claim 2 and further including an individualswitch associated with each of said power sources, wherein the singleactuation of said switch mechanism closes or opens said individualswitches.
 4. The circuit as defined in claim 1, wherein said switchingmechanism isolates said power sources at one of the following: on apositive side of said power sources; on a negative side of said powersources; on both the negative and positive sides of said power sources;or on a combination of the positive and negative sides of said powersources.
 5. The circuit as defined in claim 1, wherein said switchingmechanism is a double throw switch.
 6. The circuit as defined in claim1, wherein each of said power sources is a single dry cell.
 7. Thecircuit as defined in claim 1, wherein each of said power sourcesincludes a set of dry cells electrically connected in series.
 8. Thecircuit as defined in claim 7, wherein said dry cells are selected fromone of the following sizes or types: AA size, AAA size, C size, D size,lantern type, 9 volt rectangular type.
 9. The circuit as defined inclaim 1, wherein said portable lighting product is selected from any oneof the following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, and rechargeable versions of any of thoseproducts previously mentioned.
 10. The circuit as defined in claim 1,wherein said lamp holder holds a lamp which is selected from one of thefollowing: a halogen type; a krypton type; a vacuum type; a xenon type;and a lamp which includes a filament encased in an atmosphere of a gasor combination of gases.
 11. An electrical circuit for a portablelighting product comprising: a lamp holder having a positive terminaland a negative terminal; at least two power source holders each forholding at least one power source, each of said power source holdershaving one set of positive and negative terminals for each power sourcethat it is to hold, said sets of terminals being adapted to electricallyconnect said power sources in parallel with one another; and a switchmechanism coupled in series between said parallel power sources and saidlamp holder such that, when said switch is open, said power sources areelectrically isolated from one another, and when said switch is closed,at least one of said power sources may be electrically connected to saidlamp holder.
 12. The circuit as defined in claim 11, wherein said switchmechanism is configured to connect said power sources in parallel whensaid switch mechanism is closed and to electrically isolate said powersources when the circuit is opened by a single actuation of said switchmechanism.
 13. The circuit as defined in claim 12 and further includingan individual switch associated with each of said power sources, whereinthe single actuation of said switch mechanism closes or opens saidindividual switches.
 14. The circuit as defined in claim 11, whereinsaid switching mechanism isolates said power sources at one of thefollowing: on a positive side of said power sources; on a negative sideof said power sources; on both the negative and positive sides of saidpower sources; or on a combination of the positive and negative sides ofsaid power sources.
 15. The circuit as defined in claim 11, wherein saidswitching mechanism is a double throw switch.
 16. The circuit as definedin claim 11, wherein each of said power sources is a single dry cell.17. The circuit as defined in claim 11, wherein each of said powersources includes a set of dry cells electrically connected in series.18. The circuit as defined in claim 17, wherein said dry cells areselected from one of the following sizes or types: AA size, AAA size, Csize, D size, lantern type, 9 volt rectangular type.
 19. The circuit asdefined in claim 11, wherein said portable lighting product is selectedfrom any one of the following products: flashlight, lantern, desk lamp,area light, combination area light and flashlight, front and rearbicycle light, emergency light, night light, and rechargeable versionsof any of those products previously mentioned.
 20. The circuit asdefined in claim 11, wherein said lamp holder holds a lamp which isselected from one of the following: a halogen type; a krypton type; avacuum type; a xenon type; and a lamp which includes a filament encasedin an atmosphere of a gas or combination of gases.
 21. The circuit asdefined in claim 11, wherein each of said power source holders holdsonly one power source.
 22. The circuit as defined in claim 11, whereineach power source is located in a separate container or housing.
 23. Aportable lighting product comprising: at least two power sources eachhaving first and second terminals; a lamp holder having first and secondterminals, said first terminal of said lamp holder being adapted to bein electrical connection with a first terminal of said power sources,said second terminal of said lamp holder being adapted to beelectrically connected to a second terminal of said power sources; andat least one switching mechanism for electrically isolating each powersource from each other when said at least one switching mechanism is ina first condition, and when said at least one switching mechanism is ina second condition, said first terminals of said power sources areconnected to one another and to said first terminal of said lamp holderand said second terminals of said power sources are connected to eachother and to said second terminal of said lamp holder.
 24. The portablelighting product as defined in claim 23 and further including at leastone housing for each of said power sources.
 25. The portable lightingproduct as defined in claim 23 and further including at least onehousing adapted to hold more than one of said power sources.
 26. Theportable lighting product as defined in claim 23 and further including asecond switch connected between said switching mechanism and said secondterminal of said power sources or between said first terminal of saidlamp holder and said first terminal of said power sources.
 27. Theportable lighting product as defined in claim 26, wherein said secondswitch is a single pole, single throw switch.
 28. The portable lightingproduct as defined in claim 23, wherein said switching mechanismelectrically connects two of said power sources with said lamp holder.29. The portable lighting product as defined in claim 23, wherein saidswitching mechanism includes means for an operator to select which powersource or groups of power sources are to be connected in parallel witheach other and connected to said lamp holder.
 30. The portable lightingproduct as defined in claim 23, wherein each said power source is asingle dry cell.
 31. The portable lighting product as defined in claim23, wherein each said power source is a set of dry cells connected inseries.
 32. The portable lighting product as defined in claim 31,wherein said dry cells are selected from one of the following sizes, ortypes: AA size, AAA size, C size, D size, lantern type, 9 voltrectangular type.
 33. The portable lighting product as defined in claim23, wherein said portable lighting product is selected from any one ofthe following products: flashlight, lantern, desk lamp, area light,combination area light and flashlight, front and rear bicycle light,emergency light, night light, and rechargeable versions of any of thoseproducts previously mentioned.
 34. The portable lighting product asdefined in claim 23, wherein said lamp holder holds a lamp which isselected from one of the following: a halogen type; a krypton type; avacuum type; a xenon type; and a lamp which includes a filament encasedin an atmosphere of a gas or combination of gases.
 35. A portablelighting product comprising a switching mechanism and a lamp holderhaving two terminals including a first terminal adapted to beelectrically connected to a first terminal of at least two powersources, a second terminal of each of the power sources being adapted tobe electrically connected to a switch mechanism, whereby a secondterminal of said lamp holder is adapted to be selectively electricallyconnected to the second terminal of the power sources when said switchmechanism is in a first condition such that each of the power sources iselectrically connected to said lamp holder in parallel, said switchmechanism being adapted to adopt a second condition in which the powersources are electrically isolated from each other.
 36. A portablelighting product comprising: a housing defining respective chambers fora plurality of power sources; a light source portion associated withsaid housing including a holder for a lamp; and electrical circuit meansincluding switching means adjustable between a first condition in whichsaid lamp holder is electrically connected in parallel with said powersources, and a second condition in which said switching means breaksrespective electrical circuits linking said lamp holder and the powersources and linking the sets of power sources.
 37. A portable lightingproduct comprising: a lamp holder having two terminals with a firstterminal being adapted to be in electrical connection with a firstterminal of at least two power sources and a second terminal of saidlamp holder being adapted to be electrically connected to a secondterminal of the at least two power sources; and at least one switchingmechanism for electrically isolating each of the power sources, and forselectively allowing only one of the power sources to be in electricalconnection with said lamp holder at any time.
 38. A method for operatinga portable lighting product circuit which includes a lamp holder andwhich contains at least two power sources adapted to be coupled inparallel and selectively connected to said lamp holder, said methodincluding the step of electrically isolating each of said power sourcesfrom each other when said power sources are not electrically connectedto said lamp holder.
 39. The method as defined in claim 38, wherein eachsaid power source is a single dry cell.
 40. The method as defined inclaim 38, wherein each said power source is a set of dry cells connectedin series.
 41. The method as defined in claim 40, wherein said dry cellsare selected from one of the following sizes or types: AA size, AAAsize, C size, D size, lantern type, 9 volt rectangular type.
 42. Themethod as defined in claim 38, wherein said portable lighting product isselected from any one of the following products: flashlight, lantern,desk lamp, area light, combination area light and flashlight, front andrear bicycle light, emergency light, night light, rechargeable versionsof any of those products previously mentioned.
 43. The method as definedin claim 38, wherein said lamp holder holds a lamp which is selectedfrom one of the following: a halogen type; a krypton type; a vacuumtype; a xenon type; a lamp means which includes a filament encased in anatmosphere of a gas or combination of gases.